They shall be known as Bush's Laws of Motion

from now on.

the events of 9/11 prove one thing: the known laws of physics are out of date and require immediate updating, in light of the official reports. because the laws of gravity are so 17th century. and Isaac Newton was obviously a conspiracy nut trufer.

8. "post-9/11 physics"

... is exactly the same as pre-9/11 physics, despite the "truth movement" attacks. For example, you can find an actual-physics-based explanation for the "near free fall" acceleration of the collapse in this paper by Dr. Frank Greening. If you don't like that one, there are plenty of others that take completely different approaches and arrive at the same general conclusions.

The mere fact that you're baffled by the collapses doesn't mean any new physics are required to explain them. Maybe you're a little too willing to be baffled...

20. interesting perceptions

I guess we could quibble about the definition of "explosions" -- that's been done extensively over the last decade.

But if you really believe (not that you said this) that many eyewitnesses share your opinion that the Twin Towers were demolished by explosives, then NIST is the least of your problems. The people who believe that generally aren't eyewitnesses; they seem disproportionately to be people who spend lots of time staring at videos. If eyewitnesses tended spontaneously to form the impression that the towers were demolished by explosives, then the movement wouldn't have to seine for a handful of people to say so at its events; people would have been saying so all over New York City.

It's logically possible that the eyewitness testimony could support an explosive demolition scenario. But it's remarkably hard to get folks to try to lay out such a scenario -- and I can't think of anyone who has tried to develop such a scenario around eyewitness statements. There must be someone, somewhere, but it rarely if ever happens here. I've interacted with a bunch of people who believe in CD, and I can't think of any who seemed to have formed their view based on eyewitness evidence.

13. apparently George Bush has discovered a new law of physics.

15. Common understanding?

The "common understanding" of how the buildings fell is still based on FEMA's pancaking model, which NIST declared non-viable. NIST never provided a collapse progression model of its own, and few "common folk" have bothered to read Bazant.

So there really is no "common understanding" of the WTC destruction that's based on any kind of realistic or credible model.

62. Excellent point, jester

For three years, FEMA's zipper/pancake theory was conventional engineering wisdom. Then in 2005 NIST overturned the zipper/pancake theory--and with no debate, discussion, hand-wringing, or defenses, the column-failure theory becomes
conventional engineering wisdom.

21. Do you know the difference

between a cartoon and an illustration?

or should only one of them reach the ground at all?

No.

Upon being dropped from the crane, you're saying the left upper block reaches the ground after smashing through the entire length of the much more massive lower block? Going through the path of most resistance? How in the world does that work? By applying Bushonian laws of physics? Or should I say Nistonian? Magic? David Copperfield? Wow.

25. Nobody, anywhere, has explained how that would happen

The towers when intact and static can support a few times their own weight. How then can the same tower withstand a force many times that after failure has already occurred and not collapse further. You are imagining some new type of physics.

26. this is where the word "cartoon" is hard to resist

To put AZCat's point about local failure more vividly, you might as well argue that a brick can't smash through a car windshield because, after all, the car has so much more mass than the brick.

Let me attempt to anticipate a likely defense mechanism: yes, yes, of course that is not a good model of the tower collapses. It isn't intended to model the tower collapses; it's intended to illustrate the gaping hole in your reasoning. That "more massive object" isn't just an object; the "lower block" isn't just a block. Your model neglects a really basic fact about a building: it's, y'know, built. It isn't a point mass; it has components and structure.

Of course, the "upper block" isn't just a block, either. Damage is occurring to both the upper floors and the lower floors; ever more mass is falling, some of it within the footprint of the tower, some of it outside. The upper floors don't have to remain intact all the way to the ground (or the pile), nor do they have to smash everything in their path.

If you can't even wrap your head around this possibility -- if you can only imagine that the upper floors drop onto the top of the lower floors and rest there, because there are more lower floors than there are upper floors -- then I guess you'll be pretty puzzled by the professional literature.

28. I like the car analogy

They might as well claim that the towers couldn't have collapsed because the towers were attached to the earth; and the earth is far more massive than the top sections of the buildings. It's essentially the same argument they are apparently already making taken to its logical extreme.

29. I actually thought about something like that

I decided that it is more appealing (in general) to argue that the windshield is part of the car than that the towers are part of the "built earth." Either way, you have a model that would be fine for some problems, and fails miserably in others.

People who trash the various Bazant models, but seem oblivious to the holes in their own models, don't really seem to understand what models are for. I think that is unfortunate quite apart from any particular debate.

63. The Bazant model bears no resemblance to reality.

The persistence of 40 stories of the lower core structure after the outer floors had fallen down shows that Bazant's piledriver is a myth.
Had the piledriver remained intact, it would have impaled itself on the intact lower core.

30. Do you prefer the PBS cartoon model?

Here you go:

1) so how do you explain the total destruction of the core columns, which this NOVA documentary ignores in their ridiculous pancake model?

2) how do you explain that the core columns are very massive at their base getting progressively thinner as they rise toward the top? the 'components and structure' are much more robust at their base then they are at the upper block. how is it possible for the latter to destroy the former? do you have a model that can illustrate this phenomena?

3) how does the upper block remain intact all the way to the bottom without destroying itself on the way down and violating the third law of motion?

35. accepting your concession and continuing...

In Bazant's drawing, the little block looks pretty intact to me, until it doesn't.
How is that possible?...

And what about the big block? Why does it disintegrate while the little block remains relatively pristine, until it doesn't?

FIFY.

Those questions are answered in the paper. Should I assume that they aren't serious questions, or that you haven't read the paper?

Against my better judgment, I'll try to answer in simple words. In that model, between the "top" and the "bottom" is a compacted zone of rubble, which increases in mass and is accelerated by gravity. As long as it is falling, that rubble is crushing the "bottom," not the "top." That is perfectly consistent with Newton's laws -- and if you can understand that the "top" isn't the only thing that falls, you'll be closer to understanding the professional literature, not to mention the video evidence.

It's not nearly enough to denounce the model as unrealistic. To justify your apparent concern with the timing of crush-up vis-a-vis crush-down, you'll not only have to make your case -- ideally with at least as much formal analysis as Bazant and Verdure -- but you'll also need to make a rigorous case that the timing matters to the fate of the towers. I am not holding my breath.

27. I gave you a link above

... to a paper that explains that, using nothing but "old-school" physics, analyzed by someone who isn't even a U.S. citizen (Canadian) much less part of the Bush administration, and you completely ignored it. It seem not to occur to you that there are a LOT of people in the world who can understand that paper, and could also recognize a valid, science-based criticism of it if one were offered. Your personal incredulity, however, is not evidence of anything but itself.

36. if one can trust Legge, then Greening made a good point poorly

Chandler had said, "Moving downward without deceleration while crushing columns designed to support several times the weight...now that's a problem" -- and Legge adds a bracketed gloss that "it would violate Newton's third law."

But it doesn't violate Newton's third law. As several of us have tried to explain, the acceleration of the falling mass will remain positive upon collision unless the reaction force of collision actually equals or exceeds the gravitational force upon the falling mass.

Greening could have said something like this: In high school physics classes, collisions between a moving object and a stationary object almost always cause the moving object to slow down -- because, generally, no other force is accelerating the moving object. (If it's a billiard ball, then gravity is trying to accelerate it right through the table, but the table is pushing back.) But if the object is falling, then the gravitational force does have to be taken into account. Newton's Third Law still applies to the collision, but contrary to Truth Physics, it doesn't dictate that a falling object has to decelerate when it collides with something.

38. You totally don't understand collisions

What's the property of collisions that causes a change of velocity of the colliding bodies? Could it be force?

What is the property of gravity that causes a change in velocity of bodies in a gravitational field? Is it also force?

So what happens when the force of gravity on a body is greater than the opposing force from the colliding object? Well that's easy. The body accelerates through the collision in the direction of gravity - only the acceleration during the collision is not as great.

39. Especially collisions between two non-solid structures with pieces to break off. n/t

41. You should really be asking AZCat these questions.

He's the one who's having problems with this concept.

Nothing you have said here contradicts what I said. Do you understand this?

But then you're trying to take these everyday common sense principles and stretch them to imply that gravity can pull the top portion of a building through itself at a rate just a little bit under free fall. It cannot. There is no theory or model existing today that shows this can happen. It cannot.

44. Really? Because IIRC you were the one making pretty bold statements...

that directly contradict the SECOND law (and then got hostile when I pointed this out).

Your ignorance of physics fundamentals is going to constantly interfere with your understanding of the various models of the collapse. I suggest rectifying this, otherwise you're continually going to be a laughing-stock here.

236. I don't think you're properly interpreting the NIST reports.

By calculating DCRs in excess of 1 (based on their analysis of impact damage and subsequent fires) and examining the sequence of failures that likely resulted, the NIST demonstrated a probable collapse initiation (i.e. a falling mass).

239. And they did all that in one narrative paragraph with no calculations. Impressive! nt

241. You need to actually read the report.

If you did, you'd find a lot of your arguments to be incorrect. Like this one. I suggest you do more than read the summary as well, since that may summarize topics that get much more detail elsewhere in the supporting documents.

46. Greening was correct

Newton's third law does not apply to collapsing buildings the way that Chandler is applying it. The irrefutable proof of that is that Chandler's analysis would predict that Verinage demolitions are impossible without weakening all the floors.

In fact, they proceed very much like the Greening energy transfer analysis that you would like to avoid discussing. I personally find it jaw-dropping that anyone could watch a Verinage demolition and still not see that Chandler's analysis cannot possibly be correct. In all the "third law" blather the "truthers" dumped on Greening in its frantic effort to find an excuse to dismiss his other arguments, I can't find much understanding at all of what he was really getting at, which was Chandler's obviously improper handling of the dynamic, gravity-driven scenario. "Truthers" seem to think that attacking Greening's attempt to explain what was wrong with it not only somehow validated Chandler's analysis, it also discredited Greening's collaboration with Bazant, Le, and Benson on a paper that "truthers" apparently can't refute and so resort to personal attacks on all of those authors. But when the smoke cleared, Chandler's interpretation of the collapses was just as idiotic as it always had been, whereas Greening's analysis explains both the WTC collapses and Verinage demolitions in a way that agrees with observation.

And, I see you would also like to ignore my point that Bazant and Greening aren't the only people who have analyzed the collapse and came to the same conclusion: There is no need to resort to bizarre explanations involving imaginary causes for which there is not a shred of credible evidence. On the other hand, you expect us to be impressed with YouTube videos that conclude that Verinage demolitions must be impossible because they violate laws of physics? No thanks.

47. Chandler would not see your point about verinage

I think he would say that the Balzac-Vitry verinage proves his point, because the upper block decelerated after impact. In fact, that's what he seems to be saying in the video that jesters linked to in the NTA thread. Of course, his argument is a mess.

I may have the 'history' wrong, but it seems that Chandler shifted from arguing that impact entails a change in acceleration to arguing that it entails a period of negative acceleration, perhaps not even noticing that his argument had changed.

48. That was Chandler defending the Szamboti's "missing jolt" theory

... by saying a jolt was present in Balzac-Vitry so we should see it in WTC. What I'm referring to is his North Tower Acceleration video. Following the logic of that video, since the Verinage demolitions also show the buildings collapsing at about 2/3 g acceleration, then the structure below was only resisting 1/3 of the weight of the structure, whereas it had been designed to withstand 3 times the weight, leading to the conclusion that the Verinage people are secretly destroying the structures through some means other than dropping the top on the bottom and letting gravity do the rest. To the best of my knowledge, Chandler has never addressed that aspect of Verinage, but it would certainly be entertaining to see him try.

49. well, I was trying to get at that video, too

I think part of the problem is that, as we discussed before, it's hard to tell what he intends to argue. In his Balzac-Vitry analysis, he says that the top is accelerating at -8.5 m/s^2 initially, then at -2.1 m/s^2 for about 0.8 s "as the contact begins," then at +3.3 m/s^2 (deceleration relative to gravity) for about 0.4 s when the two sections "fully engage." Hmmmmm. Wow, that's facially weak. (Just what does Chandler think is happening for all that time between the beginning of contact and full engagement?) But anyway, I mention the numbers because I'm not sure what you have in mind by "about 2/3 g acceleration" -- maybe an average, maybe different demolitions.

I imagine Chandler would say that you completely missed his point: his argument that the structure below is only resisting a fraction of the weight of the falling structure (to paraphrase your paraphrase) applies unless the falling block "actually impacts" the structure below (around 2:05 in the NTA video) -- and we know that it didn't because of the (supposedly) uniform downward acceleration.

Of course, that raises the question what Chandler thinks is happening to provide that resistance. (IIRC, Bolo tried to get at that.) Hell, I'm not sure I can enumerate all the questions it raises.

50. The 2/3 g is my own approximation

... as being about what you get if you consider just the total collapse time and distance, i.e. it's just the average acceleration. But again, I claim that the problem with Chandler's WTC analysis is that that's also just looking at an average acceleration, so if Chandler wants to claim it's fundamentally different from a Verinage, he needs to explain why the averages are so similar. A bigger problem is that apparently more careful measurements have detected decelerations in the WTC collapse, so Chandler's premise is simply disproved.

51. OK, that's a pretty good response :)

It's another way of seeing why Chandler ought to be surprised that the towers are falling so slowly, if he thinks that the bases are being sequentially blown away (or whatever he believes). It might even reach someone.

Chandler doesn't think he is "just looking at an average acceleration." But even his own measurements indicate changes in acceleration, which he apparently rationalizes as within measurement error. (And, as I said in the other thread, maybe they are -- but either way, he obviously hasn't demonstrated "uniform downward acceleration.")

I've been idly curious how much one could conceivably infer from the closest possible analysis of the videos. Certainly Chandler's 5 Hz results seem compatible with actual deceleration, or not. I'd be wary of calling the finding you describe a "bigger problem," since I wouldn't want to risk helping Chandler move the goalposts the entire length of the field -- but, if it is any good at all, at least it underscores how weak his analysis is.

ETA: OK, I came across a thread where femr2 lays out the evidence for decelerations, and Tony Szamboti dismisses it as measurement error. About what I would expect.

ETA2: Oops, strike that: Szamboti dismisses it as deliberate obfuscation: "Anyone who really wanted to muddy the waters might claim to be MIHOP while offering confusing data and positions, which is all I have really seen you attempt to do." Damn those faux MIHOPers with their confusing data!!!!

52. With the kind of free fall drop

that is posited by Bazant (and needed for collapse progression) there would be a massive jolt measurable instantly by the eye and obvious on a graph. This is the whole point. Tony Szamboti estimates a 45% loss of kinetic energy even if half the columns missed each other. The amount of resistance actually seen was less than what could support the static load. The upper section just fell through it while gaining velocity.

You can't have an amplified load without that impulse. Without an amplified load, you don't have collapse progression.

53. that is the assertion, yes

Can you imagine a scenario in which half the columns missed each other and the other half collided in the manner that Szamboti imagines -- one that in some way resembles the observations?

I've watched people try to explain to Szamboti what's wrong with his reasoning, and I even tried it myself. You may think there is some sinister reason why he hasn't won the debate, but I really don't think there is.

76. Empty assertions must have worked very well for you over the years.

77. Empty assertions?

I'm not the one confusing basic physics principles. I'm quite comfortable with my grasp of them. You, on the other hand, need to put in some work. Have you considered tutors? I've tutored a number of people and I find sometimes a one-on-one approach can be successful for those who don't have as much luck in a classroom environment.

81. Your inability to see this is both amusing (at least to me)...

and an indication of your lack of familiarity with the subject matter. There's nothing grandiose about me pointing out the difference between the first law of thermodynamics and the first law of motion. There is, however, something grandiose about your repeated, heated defense of an obvious mistake.

87. Now your posts are making less sense than before.

Initially you were just wrong, now you're incoherent. Is this strategy intended to distract from your inability to differentiate between basic physics concepts? It is obvious to those with sufficient knowledge that the first law of motion (which you should have referenced) is substantially different from either the first law of thermodynamics or conservation of energy. You, on the other hand, continue to confuse them.

This difference between you (who can't tell the difference) and me (who can) means that we can't have an interesting conversation about the subject at hand, because you lack the foundational knowledge necessary to have a relevant opinion. Instead this subthread has degenerated into you becoming defensive and incoherent when challenged. That's not very worthwhile, unfortunately, and this subthread probably deserves to die a quiet death.

89. There is nothing incoherent about pointing out that someone who pretends to be a cat

can not also pretend to be a qualified professional who has all the answers but just can't be bothered to share them because they're oh so complicated.

That posture may have been very effective over the years in intimidating honest people with honest questions (and certainly it requires little energy of you--you can simply recycle the same vague grumbling as always), but it won't work on me.

90. Who is pretending to be a cat?

That is a very strange claim, and doesn't appear to have anything to do with the topic of this sub-thread. What is of interest, however, is your apparent inability to understand the difference between a couple of basic physics concepts, and how that interferes with a productive conversation about the collapses of September 11th. Care to comment on that, or do you find a discussion of cats to be more your style? If so, I suggest you seek other areas of this forum - we're not particularly cat dense here.

91. The difference is irrelevant to the point, which it seems you are trying to obscure.

The issue was changes in acceleration due to the absorbtion of kinetic energy in doing work processes on the buildings' structure, and the fact that energy can be neither created nor destroyed, and the need for an accounting of the energy budget of the collapses.

And you want us to run off after a pedantic red herring.

It seems that you are blind to the fact that anonymous internet posters have no professional credentials, and only a fool would believe that they do.

98. I don't think you have a very good understanding of basic physics.

Do you know what a "free body diagram" is? Maybe you should look up some examples, and then try drawing one for the situation you're trying to understand. Then maybe(!) you'll understand why you're wrong. You should probably write out the equation form of the law of conservation of energy while you're at it, and take a close look at the variables included.

Tony has a similar problem to yours, that his opinion of his technical skillset is far higher than actually warranted. Too bad for you guys that it is immediately obvious to qualified people who aren't afraid to correct your mistakes.

99. Maybe you should try making your points instead of merely implying that you have one. nt

100. My point is quite simple - you are wrong.

The fundamental equations are quite simple, and your mistakes become apparent once you compare the equations to your claims, or if you draw a simple free body diagram.

A supplemental point is that your grasp of physics is so poor that you can't even work out why you're wrong, even with hints from me. That point doesn't need extra evidence from me - you're doing a fine job supporting it on your own.

Of course, the one thing I can't overcome is your (rather ironic) certainty that you're right, no matter how obvious your wrong-ness is to those who are more capable.

102. If you think it's that simple...

then why don't you show your work?

C'mon, you claim to be familiar enough with the laws of physics to make sense of them - this should be easy. What's the equation that you think supports your claim that "impacts necessarily reduce the kinetic energy"? Please write it out, so we can point out where you went wrong. Or you could draw a free body diagram - that should work just as well.

Or you could just admit you're unqualified to engage in the discussion and save a little face.

You keep talking about kinetic energy, but you are missing something else important. Why don't you think about what comprises the energy system for a falling body, and what concepts might be absent from your model?

Hostile retorts aren't going to improve the quality of your work, unfortunately. You should just relax and try to learn a little.

130. More empty claims from someone who claims to be a cat.

134. This one is clearly not empty.

Your posts are substantial evidence of your lack of understanding of physics fundamentals. You haven't even demonstrated an interest in exploring the error and possibly learning something in the process, instead choosing to waste time with irrelevant posts about cats. Why is that? Are you that concerned with admitting ignorance that you'd rather maintain an increasingly bizarre defense of your mistake?

140. I am not interested in your obfuscation and vaporware.

There is nothing bizarre about my arguments. Apparently you've been able to function as some kind of Great and Powerful Oz here on this board and frighten everyone away with your vague allusions to your own omniscience, but it won't work with me.

111. As an aside, can you start making videos or diagrams?

Usually that's when the most amusing content is created. If you try hard enough, you might end up in the category with such greats as spooked911's rabbit cage, petgoat's rake-on-rake, or Richard Gage's cardboard box video. I sincerely feel you have what it takes to succeed.

123. I understand the principles just fine. nt

128. No, you don't.

I'm not sure how many times I need to point you in the direction of a major mistake in your energy equation before you figure it out. It took Tony Szamboti somewhere around a year (IIRC) before he saw the light - are we going to see a similar delay with you?

121. Nothing like cardboard for representational scaling of forces, huh?

That's the difference between architects like Gage and competent professionals - one group understands that you can't just stack a bunch of cardboard boxes and expect dynamic similitude, and the other doesn't.

It's only of minor impact, if all you care about is pandering to the uneducated. The rest of us will have to be excused while we obsess about dimensional analysis because we think it's important (which it is, kids - don't let Ace Acme lead you astray).

165. Huh. This isn't going to get better for you.

The boxes fail as an analog for the towers because the physical principles rely on similitude. If you don't have that, then the boxes don't mean anything. This is why Richard Gage is mocked for his video, because he tried to use the boxes to say something that they simply can't.

170. They really don't apply the same way.

The relationship between the relevant aspects of the two objects (building versus cardboard box) is different. Mass and area scale differently (hence the square and cubic relationships), so even if you built your scale model of the same material it wouldn't behave the same as the larger object. Since Gage was trying to show physical similarity, he was relying on dynamic similitude, except he can't. Because his model doesn't have it.

So no, he can't use the cardboard boxes to demonstrate the laws of physics that apply to buildings.

172. Nobody said they would behave the same. It's a demonstration of principles.

You have spent so many years pontificating on obfuscatory minutiae that you can't see the Big Picture.

Gage was not claiming any physical similarity. It was a joke. He had a dry, two-hour lecture, much of which was over the collective head of his audience, and he injected a moment of levity with a perfectly valid demonstration of physical principles that are applicable equally to cardboard boxes and to buildings.

There was certainly no claim of dynamic similitude. And yes, he can use cardboard boxes to demonstrate the 1st law of thermodynamics and Newton's 3rd law. Do you claim those do not apply to cardboard boxes? Do you claim those do not apply to buildings?

173. I claim Gage doesn't understand the principles he was trying to demonstrate.

And I claim that you cannot use cardboard boxes to demonstrate how those principles apply to buildings (at least those buildings that are not constructed of cardboard and are of a similar size). This is because they lack dynamic similitude, a concept of which both you and Gage are (or were - you can at least type it now) apparently unaware.

176. The dynamic meme has been part of the landscape since Bazant ca. 9/13/01

So no, neither Mr. Gage nor I were ignorant of it.

I'm sorry that you don't understand the principles that Mr. Gage was legitimately demonstrating with cardboard boxes, but that's not my fault. Some guys can't see the forest for the trees--especially if they don't want to.

187. Gosh, it's almost like that matters!

All these professionals are saying it does, so maybe you should consider it rather than poo-poohing the idea. It may come as a shock, but you and Gage aren't the most qualified of people and if a large group of professionals disagrees with you then it's probably because you're wrong.

193. Haven't you read all the NIST literature?

It's somewhere in the mess of documentation, a whole list of people who support the report. Then you have the authors of the report itself, who are many in number. One assumes they count as "professionals".

199. That's a neat way to dismiss a whole group of people...

whose opinions would normally be worth considering. Pretty convenient, especially when the opinions of those people are contrary to the theories you'd like to promote.

There are plenty of people who have read all the NIST reports. Just because you can't imagine doing it doesn't mean it doesn't (and hasn't) happen. That's an "argument from incredulity" and is pretty common with people of your disposition.

201. A whole secret list of a secret group of secret people you can't name because it's a secret.

203. To be honest, it's been so long since I've looked at the NIST reports and their web pages...

I'm not sure where the information is listed. You see, this is old news for building professionals. We stopped discussing the interesting stuff years ago, after we worked out the kinks with the implementation of the NIST recommendations in the relevant codes and standards.

212. Oh, so the secret names you can't name are publicly available. I see. How long have you indulged

214. It's been years since I saw the list.

One would hope that a person like you who claims to be aware of the NIST's flaws would have come across the list as well. Or have you even bothered to read any of the reports you continue to disparage?

218. Your ignorance of physics and building science specifically...

means that your opinion of the completeness of the NIST reports is irrelevant. Those of us who do have a better understanding do not generally agree with you. The reasons have been gone over multiple times, and just because you refuse to accept them doesn't mean they're any less valid.

226. The initiation is the key.

The rest is obvious to experienced professionals. The NIST was not tasked with explaining basic physics to laypeople. I'm sorry if you don't grasp the principles involved, but I don't feel responsible for your incompetence. I'm pretty sure the NIST doesn't either.

231. 2100 architects and engineers? Really?

Where do I see this list? Because it isn't from AE911Truth - they don't have nearly those numbers. Otherwise, it's just a bunch of ill-informed laypeople chattering about something that they lack the technical chops to understand adequately.

238. Can he still be counted as a supporter?

I wonder if there needs to be some sort of a legacy page, where people like him can be kept separated from those who are still active or alive.

Are those numbers supposed to impress me? I've seen the efforts of some of that group, and it's not the highest quality work I've seen. It would be more impressive if they could come up with something more than an ad campaign after all these years.

221. Now I remember where I saw them.

It's in the public comments on the draft versions of the report. There are lots of organizations and individuals who responded during the comment periods, and you can find support for the NIST reports in those comments.

I had gotten rid of all the draft NIST report stuff I had years ago, not realizing that I didn't have a separate copy of the comments. That's why I couldn't find the names initially, because the comments weren't included in the final report.

227. Gosh, if only you could read them and find out.

But I guess looking up the comments on the NIST website and finding out for yourself is not your intent? Would you rather trust the word of an anonymous internet poster instead of verifying on your own?

114. Of course not. The collapse was too complicated for diagrams.

Or so NIST tells us. Of course maybe computers are more powerful now, and maybe modeling software is better, so maybe instead of hiding behind the legend that their computers weren't up to the job, maybe it's time to open up a new investigation.

I would be curious to hear your rationalizations in opposition to trying to model the collapses. Too much money, right? One Chinook helicopter costs $30 million, but we can't afford $15 million for proper investigations of 9/11.

120. The collapses may have been, but your example shouldn't be.

Why don't you just make a simple free body diagram? It shouldn't take very long. Or it shouldn't, provided you're a competent person. Other people might have to resort to other methods, like obfuscation.

125. Let's just use NIST's free body diagrams as a point of discussion.

127. Why wouldn't the NIST use free body diagrams?

Oh right, they are more sophisticated, and used complicated software tools that do the same thing (only a million times over). Free body diagrams are a tool more useful for simple problems, like our discussion.

167. I've been quite clear.

I am not going to take the blame for your failure to understand what is a rudimentary physics concept. You've repeatedly shown this failure in this thread, and now you're claiming that you didn't say what you said? It's all right there, conveniently placed in the title of your posts multiple times.

169. You shift the goal posts from an energy equation to an energy balance. nt

171. Not really.

The first law of thermodynamics is an energy balance. Or are you going to reverse course and now claim that wasn't the equation you were thinking of? Regardless, claiming kinetic energy is the only quantity of interest is quite... illuminating.

174. You're not claiming that heat and entropy are significant factors are you?

175. Gosh, so close and yet so far.

Nope, you're still not getting it. Oh well, like I said - it Tony Szamboti quite some time to figure this out, and he had the benefit of relevant schooling to rely on. Unfortunately Tony has an attitude similar to yours, and is resistant to correction.

190. Thanks for the tip. Maybe I'll look into it, but I don't see why.

NIST claims they didn't analyze the collapses. That right there indicates the need for further investigations. You trying to poke holes in in some guy's theories does not change the fact of NIST's inadequate work even if you're right about the theories. I'm not interested in alternative theories. I'm interested in getting complete and honest government investigations.

213. That's because there's no point in spoon-feeding you information.

I've seen how poorly received that is by you, and it's just not worth it. I'd prefer you actually figure out the mistake on your own (with perhaps a little guidance) because I think the odds are better that you'll learn something this way. See? With my method, everybody wins!

Your opinion is quite irrelevant on technical matters. Please either address topics where you can demonstrate competency, or perhaps work to increase your competency in the fundamentals of physics.

177. By the way - this is why I corrected you way back in post #69.

The first law of thermodynamics is going to get you on the wrong path. You really need to use a different relationship in order to see what you're missing. Perhaps now that you're thinking about the problem a bit more this mistake will become apparent.

182. Totally missed it, sorry.

The limitations on modelling don't have to do with computing power (much, anyway - there are some recent developments that might help out), they have to do with the nature of the collapses. Or any nonlinear phenomena, really. It's the same reason that the billions (trillions, possibly) of dollars spent to model the weather all have the same crappy failure rate. Minute differences in the initial states of the systems (real versus modelled in our case) can result in rapid differences in the outcome. This is why it's meaningless to dissect the WTC7 simulation, because it's not going to be a very good representation of the collapses no matter how sophisticated the model gets.

183. I wasn't talking about WTC7. I was talking about the towers.

And again, the problem is not the complexity, but the simplicity of the collapses.

One approach would be to see how many inputs of sudden structural weakening would be necessary to keep the collapse centered and "essentially in free fall" and then gradually reduce the number of those inputs to try to approach a model of a natural collapse behaving in that way.

As to WTC7, why not construct a model based on the theory that the collapses of the penthouses were achieved by cutting beams at the top of the building, and the building was then brought down by cutting core columns. Why not do it? What are you afraid of?

188. WTC7 was the one NIST modelled the collapse for. That's why it's relevant to the discussion.

The problem is the complexity of the collapses. It's a common modelling problem, and saying differently doesn't change the nature of modelling. It just makes you look like you don't know what you're talking about.

If you want to model the collapses then what's stopping you? As I've said time and time again, do your own work rather than relying on the NIST to do it for you. It's obvious you're going to dismiss any of their results anyway, so why not skip that step and get right to the interesting part?

192. Actually, it is the job of every concerned citizen...

to check the claims of government organizations. Obviously not everyone is going to be qualified for technical tasks, but that doesn't relieve the responsibility to do what we can as active participants in a democracy to keep our elected and career public servants honest.

If you can't model the collapses because of your limitations to your technical skillset, that's understandable. But please don't try to claim it's not your job - that denigrates the whole concept of an active citizenry.

200. I'm glad I'm being a concerned citizen, then.

I like to think I'm doing my part to ensure arguments in this forum meet a certain standard. However, there are some posters who refuse to agree that making arguments that are based on a flawed understanding of physics is not acceptable.

205. Your claims to a superior knowledge of physics are empty.

A lot of people who read the nonsense posted at JREF by anonymous internet poster then consider themselves qualified to pass on the same nonsense (anonymously) to others.

Your claims are not just empty, they are also immaterial. There is no need to argue the laws of physics when the 9/11 Commission Report and the NIST Twin Towers report and the WTC7 report are demonstrably incomplete and dishonest.

Do I need to remind you of your repeated posts where you claimed the definition of kinetic energy was the energy equation?

Your incompetence regarding physics pretty much negates any opinion you might have about the technical information included in the NIST works. Why don't you find something where you have some competency? Then you might have a relevant opinion.

209. How quickly you forget.

Too bad it's just upthread a-ways, where anybody who cares can go see exactly where that happened.

And now we're just continuing in the same vein, when you could have spent all this time learning how to correct your mistakes! Why, if you'd only taken the time you've likely spent arguing about physics without a clue, you could probably have earned at least a bachelor's degree in engineering. Then you would at least be marginally less irrelevant!

54. Just one little problem with the Verinage technique

57. What problem, for whom?

Vérinage is a technique suitable for any building with parallel load-bearing walls, but is not suitable for buildings with columns, because the basic technique is to use cables and jacks to cause pairs of parallel walls to fold and collapse simultaneously. It doesn't have anything to do with the material, e.g. it can be used on buildings with reinforced concrete load-bearing walls, but isn't suitable for buildings with reinforced concrete columns. So Vérinage isn't used on steel-framed buildings simply because those buildings have columns instead of load-bearing walls, not because steel is indestructible.

None of which has anything to do with what we've been discussing here. The relevance of Verinage to this discussion is that it's an actual example of the kinetic energy of the top of a building overcoming the structural strength of the bottom by simply falling on it, just as structural mechanics predict.

But now that you mention it, the fact that Vérinage isn't used on steel-framed buildings IS something of a problem for Chandler and Szamboti: They need to justify why they are comparing fine details of Vérinage collapse accelerations to the WTC towers and drawing conclusions from the differences if we're talking about building materials with different behavior characteristics. (That would be in addition to justifying doing "jolt" comparisons when Vérinage tops always fall squarely on the the bottoms, not tilted like the WTC towers.)

59. The question is, what was your point?

Specifically, you claimed there was some "little problem." I asked you, what problem and for whom is it a problem, and you haven't answered. Are you under the impression that anyone suggested Verinage at the WTC and you are refuting that? Or are you just pretending to have an argument, somewhere?

40. I don't see what the problem is.

The impact of the planes ripped apart part of the load-bearing structure in the building. The load was re-distributed to the remains of the structure, creating localized areas of stress that were at or near the ultimate strength of the materials, the concrete and steel.

As the building swayed in wind, as the fire heated the concrete and steel, the structure progressively weakened as more and more joints deformed or failed. The affected area was in the immediate vicinity of the impact site, naturally.

Eventually, the structure in the affected area weakened enough to cause a very rapid chain-reaction failure of the joints, and the part of the building above the affected area tilted and began falling.

A couple of hundred thousand tons of steel and concrete dropped onto the rest of the building, which was unable to cope with the kinetic energy and momentum transfer. Especially when the dropped load isn't hitting even. The top of the bottom part of the building absorbed the full brunt of the equivalent of a supertanker slamming into it, the jolt shattering concrete, twisting and rending steel, and popping welds and rivets. The upper part of the building continues to fall, with the bottom part of the building crunching steadily downward under the accelerating mass of the upper part.

Every second, the enormous momentum and energy of the upper part is crashing into a structure designed only to hold static loads. The structure is continually overwhelmed all the way down to the bedrock by forces dozens or hundreds of times the design load.

It's like a rope breaking under gradually increasing strain. A few fibers might pop, then all of a sudden... catastrophic failure.

On an episode of "Mythbusters" they were trying to find out if you can rip the transmission of a car out by bolting a cable between the rear axle and, say, a telephone pole.

Despite the fact that the cable was plenty strong enough to pick up the car if it was, say, attached to a crane, the car was able to easily break the cable after getting a few dozen yards of acceleration.

There ya go. When static, the structure of the WTC towers was plenty strong enough to hold the weight. Add motion, and all bets are off.